Optical communications systems are widely used for carrying very large quantities of information with low distortion and at low cost over great distances. Optical systems are also promising for such purposes as computing because of the inherently high speed at which they can be operated. For these reasons, considerable development work has been done on components of optical communications systems, such as photonics packages or modules. Photonics generally refers to devices that share both electronic and optical attributes, such as lasers, which generate coherent light in response to an electronic signal, and photodetectors, which generate an electronic signal in response to light.
In making photonics packages such as laser source modules, it is important to make components such as the laser and the laser output lens to be in precise predetermined alignment. Since many such modules are typically required for a system, designs are required that permit mass-production by operators having a moderate level of skill, while maintaining the required alignment criteria.
During the operation of a semiconductor laser source module, in which light is directed from a front facet of the laser through a lens to an output waveguide, it is often desirable to project light emitted from a rear facet of the laser onto a photodetector for monitoring operation of the laser. In providing such a laser source module, lenses on opposite sides of the laser may be provided for projecting light, both toward an output optical waveguide and toward a photodetector, and such lenses must be mounted in precise predetermined alignment or registration with the semiconductor laser. Thus, there is a need in the industry for methods for mass-producing laser source modules with a sufficiently high degree of precision to assure the accurate alignment of a lens with the laser; there is a further need for a module in which lenses are accurately aligned with the laser on opposite sides of the laser.